Visual and audio information is often stored on a tape for playback at a subsequent time. For example, visual and audio information relating to popular motion pictures is stored on tapes. These tapes are rented or sold at neighborhood stores. A popular movie such as "Aladdin" or a movie winning an Academy Award has millions of taped copies distributed to satisfy the demands of purchasers and renters. Substantially all of these taped copies have to be made available at a pre-selected release date in order to satisfy the pent-up demand of viewers for such taped copies. Although the demand for movie rentals and sales is great, it still seems to be increasing significantly from year to year.
Visual and audio information on tapes is not only provided in the form of movies for entertainment. It is also provided in large volume for business purposes. For example, large corporations deliver messages in the form of tapes to their sales personnel to acquaint such sales personnel with the construction, operation and advantages of new products. Since large corporations employ large numbers of sales personnel, many copies of such messages have to be prepared for distribution to such sales personnel.
The visual and audio information on most tapes is in magnetic form. One reason is that information in magnetic form can be relatively easily and inexpensively reproduced. For example, most reproducing apparatus in the home use magnetic heads to read the information stored magnetically on the tapes when the tapes are inserted into such apparatus. Another reason is that tapes with information recorded in magnetic form are less expensive to reproduce than tapes in other forms such as in optical form.
One type of tape for recording information in magnetic form has a thermomagnetic layer on the tape. The thermomagnetic layer may be formed from a suitable material such as chromium dioxide. The thermomagnetic layer has a Curie temperature at or above which any magnetic information on the tape is destroyed and below which magnetic information can be recorded on the tape. Thermomagnetic tape is advantageous because information can be recorded on the thermomagnetic tape at a temperature at or somewhat below the Curie temperature by pressing a master tape against the thermomagnetic layer on the slave tape at such a temperature. This causes the surface of the thermomagnetic layer to become cooled to a temperature below the Curie temperature by contact with the cool surface of the master tape. As the thermomagnetic layer cools to a temperature below the Curie temperature, the magnetic information on the magnetic tape becomes transferred to the thermomagnetic layer on the slave tape. The information on the master tape thus becomes transferred in mirror form to the thermomagnetic layer on the slave tape without having to use any magnetic heads to write information on the slave tape.
There is at least one apparatus now in use for transferring information in magnetic form on a master tape to a thermomagnetic layer on a slave tape. Although this apparatus is fast, it is large, cumbersome and expensive, and requires excessive electrical power. With the millions of copies that have to be made of a single movie such as the movie winning an Academy Award, it would be desirable to provide apparatus which is relatively inexpensive and which transfers information from a master tape to a slave tape in a minimal period of time. For example, it would be desirable to provide equipment which is relatively inexpensive and which reproduces a two (2) hour movie in approximately thirty (30) to sixty (60) seconds without any need for using magnetic reproducing heads. Because of the desire, and actually the need, for such apparatus, a considerable effort has been devoted, and a significant amount of money has been expended, to develop apparatus which meet such criteria. In spite of such effort and such money expenditure, no satisfactory apparatus meeting such criteria has been provided to this date.
The invention disclosed and claimed in application Ser. No. 07/733,174 filed by us on Jul. 19, 1991 for a "Tape Duplicating System" and assigned by us to the assignee of record in this application provides apparatus which more than meets the criteria specified in the previous paragraph. It is able to record a two (2) hour movie in approximately thirty (30) to sixty (60) seconds such that the duplicated copy has the visual and audio fidelity of the original or master copy. It is compact so that it occupies relatively little space. This is important when a large number of apparatuses are used simultaneously in an enclosure such as a room to make duplicate copies. For example, the apparatus can be used to transfer the information on master-master tape to a master tape, and subsequently the same apparatus can be used to transfer the information on the master tape to a slave tape, all without using recording heads.
In one embodiment of the invention disclosed and claimed in application Ser. No. 07/733,174, a master tape moves between first supply and take-up reels over a pinch roller. A slave tape moves between second supply and take-up reels over a capstan. First and second guides can be respectively constructed and adjustably positioned to regulate the movement of the master and slave tapes to aligned positions on the pinch roller and the capstan. A heater disposed between the pinch roller and the second guide heats only a thermomagnetic layer on the slave tape to at least the Curie temperature. The heater is adjustable in position to facilitate the movement of the slave tape to the aligned position on the capstan. A brake shoe between the capstan and the second supply reel controls the tension of the slave tape and damps any variations in the tension of the slave tape. A brake shoe between the pinch roller and the first supply reel controls the tension of the master tape and damps any variations in the tension of the master tape.
The pinch roller is movable to a first position, locked in position relative to the capstan, in which it abuts the capstan to facilitate the transfer of magnetic information from the master tape to the slave tape. In this disposition, the pinch roller locks the heater in a fixed position relative to the capstan. The pinch roller and the associated guide are movable to a second position displaced from the capstan to facilitate the disposition of the master tape on the pinch roller and the slave tape on the capstan. The heater is pivotable relative to the capstan to facilitate the disposition of the slave tape on the capstan. The capstan, preferably of a unitary construction, receives forces to maintain the rotational axis of the capstan substantially constant.
Since the tapes pass over surfaces between the brake shoes and the capstan and the pinch roller, the tensions on the master and slave tapes are not as closely regulated at the position of transfer of the magnetic information from the master tape to the slave tape as might otherwise be desired. Specifically, the tapes pass over alignment guides which have a variable friction with time and physical conditions. This variable friction inhibits a precise regulation of the tape tensions at the abutting positions between the capstan and the pinch roller where the magnetic information is transferred to the slave tape.
In one embodiment of the invention disclosed and claimed by us in application Ser. No. 07/886,688 filed by us on May 19, 1992, for a "Tape Duplicating System" and assigned by us of record to the assignee of record of this application, a master tape movable in a closed loop including a pinch roller transfers a mirror image to a slave tape movable in a closed loop including a capstan. A thermomagnetic layer on the slave tape has a Curie temperature above which magnetic information is destroyed and below which magnetic information can be recorded on such layer. The thermomagnetic layer is heated above the Curie temperature and is accordingly lengthened by thermal expansion just before the slave tape reaches the capstan.
A first guide contiguous to the heater regulates the tension of the slave tape. A downstream portion of a peripheral surface, preferably defining a cylindrical segment, on the guide receives a pressurized fluid for sensing the tape tension in accordance with the tape width, the spacing from the axis of the peripheral surface and the fluid pressure. An upstream portion of the peripheral surface receives a vacuum adjustable to vary the spacing between the slave tape and the downstream portion. This regulates the tape tension.
The master tape is lengthened by a second guide having the same construction as the first guide to compensate for the lengthening of the slave tape by the heater and the first guide, thereby producing a true mirror image on the slave tape after the slave tape has cooled to the ambient temperature. Each of the master tape and the slave tape has a particular product of the Youngs modulus, tape width and tape thickness to provide a controlled strain on the tape when the tension on the tape is regulated.
The invention disclosed and claimed in application Ser. No. 07/886,688 provides apparatus for, and methods of, regulating the tension of the master tape at a position contiguous to the pinch roller and for regulating the tension of the slave tape at a position contiguous to the heater, which is in turn contiguous to the capstan. The apparatus and method of application Ser. No. 07/886,688 are adapted to be used in the apparatus and method of co-pending application Ser. No. 07/733,174 and to constitute an improvement in the apparatus and method of co-pending application Ser. No. 07/733,174. Co-pending application Ser. No. 07/733,174 also provides a master tape and a slave tape which may be constructed especially for the apparatus and method of the invention disclosed in such application to obtain all of the advantages provided by the apparatus and method of such application.
In one embodiment of the invention disclosed and claimed in application Ser. No. 08/026,697 filed by us on Mar. 5, 1993, for a "Tape Duplicating System" and assigned of record to the assignee of record of this application, a master tape moves from a first supply reel to a first take-up reel in a first cassette. A slave tape moves from a second supply reel to a second take-up reel in a second cassette. A pinch roller locked in a first position between the first supply and take-up reels abuts a capstan between the second supply and take-up reels to transfer to the slave tape the image on the master tape. At the end of such transfer, a signal sensing the completion of the transfer causes the pinch roller to be unlocked and to be moved to a second position displaced from the first position. In this position, the second cassette is replaceable by another one of the second cassettes for an image transfer from the master tape.
In the invention disclosed and claimed in application Ser. No. 08/026,697, the rotations of the supply reels produce eccentricities which vary the tensions of the tapes as the supply reels rotate. These tension variations are compensated at positions before the pinch roller and the capstan by springs guiding the tapes and by damping members attached to the springs. The damping members are pre-stressed to provide damped compliances in accordance with the tension variations. Stiffeners are attached to the spring ends to provide for the compliances by the springs.
Application Ser. No. 08/026,697 also discloses and claims a capstan which may be hollow and non-magnetic to receive a magnetic head within the capstan. A constant amplitude alternating signal applied to the head to apply initially rising and then decaying amplitudes to the tape as it is displaced from the head erases any image on the slave tape by providing a magnetizing force greater than that of the slave tape but less than that of the master tape. Thus, the image on the master tape is transferred to the slave tape by the abutting tape relationship.